Circuit interrupter



J. D. HILLIARD CIRCUIT INTERRUPTER Filed Nov. 4, 1938 Feb. 18, 1941..

2 Sheets-Sheet 2 v rs() ll-lll- Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates in general to a circuit breaker of the type in which an arc is drawn in a more or less closed chamber in an arc extinguishing fiuid and is subjected to a blast of fluid produced by gas generated by the arc and passed over corrugations to produce turbulence to aid in arc extinction.

In the prior art circuit breakers of this general type explosion chambers of many types have been used. These chambers or pots have been made of metal in order to provide the strength necessary to withstand the pressure generated by the arc. Such chambers have been lined with insulating material so that an arc would not strike from one of the live contacts to the casing. Attempts were then made to form these 'pots of insulating material. When the pot was formed of molded or pressed insulating sheet material, minute cracks would at times develop and the pots were then not suiiiciently rugged to withstand the generated pressures. The problem which the prior artpresented was -therefore to build an explosion pot or pressure chamber of insulating material and to provide the same with an efficient throat vent, and also to build the same from elements which could be simply, cheaply and easily manufactured by mass production.

It is` therefore an object of this invention to provide a substantially closed chamber circuit breaker, that avoids the above disadvantages and solves the above problems.

It is also an object cf this invention to provide a circuit breaker of the above type in which the arc extinguishing element can be easily and simply assembled from a stock of similar elements, cheaply and simply constructed, but yet be exceedingly rugged and ecient.

It is a further object of the present invention to provide a circuit breaker of the above type with an interrupting chamber having a throat opening extending from the arc in substantially all directions in a given plane or planes.

It is a further object of this invention to provide a throat opening of the above type that provides for expansion of the arc gases during expulsion thereof from the pressure chamber.

It is also an object of this invention to provide oil circuit breaker of the above type wherein the interrupting chamber and throat vent are formed by two similar elements yieldingly held in operative position.

It is also an object of this invention to provide a circuit breaker of the above type with throat vents extending in substantially all directions from the arc in two planes at right angles to each other.

These and other objects and advantages will be apparent from the following description when taken in conjunction with the accompanying drawings in which:

Fig. 1 is a sectional View of a circuit breaker embodying the present invention;

Fig. 2 is a sectional view of the contact and arc extinguishing structure shown in Fig. 1;

Fig. 3 is a modification of the construction shown in Fig. 2;

Figs. 4 and 5 show another modification ci the construction shown in Fig. 2, Fig. 5 being a sectional view of the construction shown in Fig. 4;

Figs. 6 and 7 shown additional modications of 15 the device shown in Fig. 2;

Figs. 8, 9 and 10 are three views of another modification of the construction shown in Fig. l, Fig. 10 being a top View, Fig. 8 being 'a sectional View taken on the line VIII-VIII of Fig. 9 and Fig. 9 'being a sectional 'front View taken on the line IX-IX of Fig. 8;

Figs. 11, 12 and 13 are three views of another embodiment of the present invention, Figs. 1l and 12 being sectional views taken on the lines XI-XI and XII-XII respectively of Fig. 13.

Fig. 1 shows a circuit breaker having a casing I5 filled with arc extinguishing fiuid. The casing cover I6 has conductors therethrough which are insulated from the casing by the bushings II. The conducting studs I8 terminate in fixed contacts I9 which support the arc extinguishing structures 25. These mem ers 25 are shown as circular plate-like pieces of insulating material such as wood, fiber, or the like, and are provided with a series of concentric corrugations on one face thereof. The members 25 form the arc ex tinguishing chamber and the throat vents through which the extinguishing fluid and arc products are expelled. The members 25 are supported on an insulating sleeve 29 surrounding a bolt 26, one of the members 25 being fastened to the fixed contact I9 as by screws 2l. The movable contacts are connected electrically and mechanically by a bridging member 23 operated by the rod 24 from a mechanism not shown.

When the contacts I9 and 20 are separated, an arc is drawn inthe substantially closed chamber formed by the members 25. The arc is subjected to a blast of the extinguishing iiuid and gas out through the throat 3l which extends substantially in all directions in the plane ci contact movement. The entire throat may not necessarily be used in some classes ci service dependent upon the voltage and current conditions. The corrugations provided on the adjacent faces of the members 25 retain a supply of fluid which will be dissociated by the heat of the arc or be atomized and blown into the ionized gas of the arc to effect circuit interruption. If plain plates without corrugations are used, they would become carbonized at fairly small currents due to the fact that the oil or other arc extinguishing fluid could not be retained on the surface of these plain plates.

The members 25 forming the pressure chamber are separate similar members spaced relative to each other. This construction permits any desired grooving arrangement to be simply and easily made, whereas if the construction was a slotted single piece construction, it would be difl'icult or impossible to cut the desired design in the opposing spaces thereof. 'I'he term similar, as used herein in reference to members such as 25, denotes members such as may be formed from substantially the same dies or have corrugations formed by substantially the same tools. 'I'he use of similar members considerably reduces the manufacturing cost from that involved in the use of dissimilar or complementary members. In the present construction a narrow blade contact such as is shown at 2U may be used. This contact may be of any desired length without interfering in any way with the operation of the breaker. The use of the narrow blade in the limited space available increases the interrupting eiiciency.

In Fig. 3 one of the members 25 is mounted to permit automatic adjustment of the space between the plates in accordance with the pressure generated. The spring 33 biases the member 25 toward the contact and allows movement thereof on the sleeve 29.

In Figs. 4, 5, 6 and 7 provision is made for expansion of the gas and arc products by a rounding off of the members 25 so that the throat 31 becomes progressively Wider. This expansion of the gas between the plates has a considerable effect upon the cooling of the gas and on the pressure and velocity between the plates, all of which greatly affect circuit interruption. In Fig. 7 an additional chamber is provided for additional storage of insulating fluid, thus assuring that fluid is available for use when required. In Fig. 6 two chambers 35 are shown. In these constructions an additional sleeve of insulation 35 is provided on the bolts 28.

In each of the constructions shown in the rst seven figures the various elements of the modifications shown may be combined. The spring biased mounting may be utilized on any of the constructions shown and such biasing may be utilized in conjunction with the curved faces of the members 25. The chambers 35 may be utilized in any of the constructions shown and an expulsion port, such as shown in Fig. 8 as 39, may be utilized, thereby allowing a vent and its accompanying blast action immediately adjacent the separating contacts.

The embodiment shown in Figs. 8, 9 and 10 utilizes a hinged structure and a reinforcing or maximum throat opening adjustment at the lower end. This construction is similar in operation to that of Figs. l to 7, however the through center boit is omitted. The insulation members 25 are supported partly by the bolt 50 carried in the square end 49 of the stud i8 and insulated therefrom by the sleeve 53. Members 25 are also held in position by rods 43 which are carried by tension members 40 mounted on bolt 50 and extending through slots 54 in the members 25. Pins 44 prevent endwise movement of rods 43 and washers 393 provide bearing surfaces therefor. 'Ihe upper ends of the members 25 are rounded off as at 45 and a cut out portion 48 is provided to allow for slight movement of the upper ends when the lower ends are moved outwardly by the arc generated pressures.

The fixed contacts 38 are mounted in the square shank 49 of the stud I8. The bolt 23 and spring 33 provide means for biasing the members 25 into the position shown in Fig. 8 and limiting maximum movement. Chambers 35 are provided in each of the members for providing an additional supply of insulating fluid at the point of inception of the arc. Expulsion ports 39 are provided immediately adjacent the separating contacts.

In the embodiment shown in Figs. 1l, 12 and 13, four similar elements 41 are supported on square shank 49 of the stud I8 by a ring 55, thus forming throat vents in two planes through the arcing region. Corrugations are provided on the inner faces of the members 41 which are of insulating material similar to the other embodiments.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A circuit breaker comprising a casing, arc extinguishing fluid therein, a fixed contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, and a plurality of similar plate-like elements supported on said xed contact and spaced apart to form a pressure chamber and a throat vent therebetween, said elements provided with corrugations on adjacent faces thereof.

2. A circuit breaker comprising a casing, arc extinguishing fluid therein, a xed contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said xed contact member to draw an arc therebetween in said fluid, and a plurality of similar plate-like arc chamber and throat vent forming elements supported in spaced relation on said fixed contact and substantially enclosing the same and provided with corrugations on adjacent faces thereof, and means providing for expansion of the arc gases in said throat vent during expulsion thereof from said arc chamber.

3. A circuit breaker comprising a casing, arc extinguishing fiuid therein, a fixed Contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, two similar members of insulating material provided with concentric circular corrugations on adjacent faces thereof and means for supporting said members to substantially enclose said contacts so that the central corrugations thereof are substantially at the contacting portions of said contacts.

4. A circuit breaker comprising a casing, arc extinguishing fluid therein, a fixed contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, and two similar spaced platelike contact enclosing and throat vent forming members provided with corrugations on adjacent Cil faces thereof and movably supported on one of said contacts.

5. A circuit breaker comprising a casing, arc extinguishing fluid therein, a fixed contact member supported by said casing in insulated relation thereto, a movable Contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, and two similar spaced plate-like contact enclosing and throat vent forming members provided with corrugations on adjacent spaced faces thereof and movably supported on one of said contacts, and means for resiliently urging said members toward said contact.

6. A circuit breaker comprising al casing, arc extinguishing fluid therein, a xed contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, a plurality of contact enclosing members provided with corrugated faces spaced to form throat vents extending from said arcing region in a plurality of planes therethrough, said throat vents extending radially from said arc substantially 360 degrees in said planes.

7. A circuit breaker comprising a casing, arc extinguishing fluid therein, a fixed contact member supported by said casing in insulated relation thereto, a movable contact member coacting with said fixed contact member to draw an arc therebetween in said fluid, a plurality of similar platelike members provided with a plurality of indentations on adjacent faces thereof and apertures therethrough and pivotally supported on said fixed contact so that said indentations form a pressure chamber and a throat vent enclosing the region of said arc and so that said apertures form expulsion ports immediately adjacent said separating contacts.

8. In a circuit breaker, the combination of a casing enclosing insulating and arc extinguishing fluid, fixed and movable contacts cooperable to draw an arc in said fluid, and means for extinguishing said are comprising similar spaced plates of insulating material having corrugated adjacent surfaces between Which said arc is drawn, the spacing of said plates forming a throat vent extending radially from said contacts substantially 360 in extent.

9. In a circuit breaker, the combination of a casing enclosing insulating and arc extinguishing fluid, xed and movable contacts cooperable to draw an arc in said fluid, means for extinguishing said arc comprising spaced plates of insulating material having corrugated adjacent surfaces between which said arc is drawn, and means for positioning one of said plates on one of said contacts comprising a member extending through substantially the center of said corrugated surface thereof at substantially right angles thereto.

JOHN D. HILLIARD. 

